Hi Vlad,

thanks for the test case. This bug is not fixed and it occurs only with some jdbc drivers.
I have the exact same problem when using the SAP HANA jdbc driver (ngdbc.jar).

Statement#isWrapperFor(type) returns true, because the wrapped class is of type java.sql.CallableStatement.
After this pseudo type check, the wrapper is blind casted to CallableStatement which results in a ClassCastException
because the wrapper itself does not implement CallableStatement (but the inner class does).

I think it is pure luck that it works with most jdbc drivers!